Generally, three-dimensional (3D) body surface imaging may be performed with a body scanner, which captures the surface geometry of the human body utilizing digital techniques. Body scanning provides noncontact, fast, and accurate body measurements. Anthropometric parameters computed by scanners include waist and hip circumferences, sagittal abdominal diameter, segmental volumes, and body surface area. Body-scanning technologies have evolved and several body scanners are commercially available. However, their high price and large size limit their practicality for field studies.
Body scanners may be based on, for example, (a) laser scanning, (b) structured light, or (c) stereo vision. In laser scanning, consecutive profiles may be captured by sweeping a laser stripe across the surface to be imaged. Laser scanning is more intricate and expensive than structured light or stereo vision methods as it may involve moving parts. Structured light may utilize a sequence of regular patterns to encode spatial information. It may require dedicated lighting and a dark environment, which makes the hardware relatively more complex than stereo vision. Also, with structure light systems images may need to be captured sequentially in synchronization with pattern projections. In the case of whole body scanning, image acquisition by structured light can be further slowed down because multiple sensing units in the system may not be able to work simultaneously; otherwise pattern projections from different units may interfere with each other. Stereo vision works similarly in concept to human binocular vision and is a passive method that it is not dependent on a light source.
Specifically regarding prior body imaging techniques, some scanners construct a 3D model of an object based on a series of silhouette and texture map images. Other scanners may obtain a 3D data set based on a grating pattern, having a sinusoidally varying intensity pattern, projected onto the surface of an object. The projected grating pattern may be shifted a number of times to generate data for the 3D model. Still other scanners may use phase measurement profilometry techniques for measuring the surface contour of an object having a surface discontinuity. Alternative scanners include a multiple view detector which is responsive to a broad spectrum of visible light. Other scanners use a pattern of vertical lines on the object-of-interest that appear to be bent differently to each camera by virtue of the surface shape of the object-of-interest and the relative geometry of the cameras. Additional scanners illuminate an object with a single plane of light producing a contour line that is viewed from two or more vantage points.